Aromatic polycarbonate resin molding

ABSTRACT

Provided is an aromatic polycarbonate resin molded body, which is obtained by molding a resin molding material containing an aromatic polycarbonate resin (A), in which: the molded body has a thin-walled portion having a thickness of 0.5 mm or less; the molded body has an o-hydroxyacetophenone content of 1 ppm by mass or less and a nitrogen atom content of 15 ppm or less; and the molded body is free of an absorption maximum in a wavelength range of from 500 nm to 600 nm.

TECHNICAL FIELD

The present invention relates to an aromatic polycarbonate resin moldedbody, and more specifically, to an aromatic polycarbonate resin moldedbody reduced in yellowing and excellent in light transmission property.

BACKGROUND ART

A polycarbonate resin is excellent in, for example, transparency,mechanical properties, thermal properties, electrical properties, andweatherability, and has been used in an optical molded article, such asa light-guiding plate, a lens, or an optical fiber, through theutilization of its characteristics. However, the light transmittance ofthe polycarbonate resin serving as one of the indicators representingits transparency is lower than that of, for example, a polymethylmethacrylate (PMMA). Therefore, a surface light source body including alight-guiding plate made of the polycarbonate and a light source has aproblem in that its luminance is low.

Accordingly, a method of improving a luminance or a light transmittancein the light-guiding plate made of the polycarbonate has hitherto beenproposed. In, for example, PTL 1, there is a disclosure of an aromaticpolycarbonate resin composition and a light-guiding plate each includingan aromatic polycarbonate resin and a thermoplastic resin whoserefractive index differs from that of the aromatic polycarbonate resinby 0.001 or more, and each having specific optical characteristics. InPTL 2, there is a disclosure of an aromatic polycarbonate resincomposition for a light-guiding plate having a satisfactorytransmittance and a satisfactory hue, the composition being obtained byincorporating, into an aromatic polycarbonate resin, a specific amountof a polyalkylene glycol having a specific structure or a fatty acidester thereof.

In PTL 3, there is a disclosure of a resin composition excellent inlight transmittance and luminance, and capable of resisting molding athigh temperature, the composition being obtained by blending an aromaticpolycarbonate resin with a specific amount of apolyoxytetramethylene-polyoxyethylene glycol having a specificstructure, and an optical molded article using the composition.

A polycarbonate resin composition to be used in the production of alight-guiding plate or the like has started to be molded in a widetemperature region in association with the thinning of a molded articlethereof, and hence has been required to have: such high heat stabilitythat its yellowing, a reduction in its light transmittance, or the likedoes not occur under a high-temperature condition; and durability at thetime of the use of the product.

In PTL 4, there is a disclosure that the incorporation of a diphosphitecompound having a specific structure and an alicyclic epoxy compoundinto an aromatic polycarbonate resin provides a molded article that isexcellent in heat stability in high-temperature molding, lighttransmittance, and luminance, and that does not cause discoloration orcracking even when exposed to a high-temperature and high-humidityenvironment for a long time period.

CITATION LIST Patent Literature

PTL 1: JP 2002-60609 A

PTL 2: JP 4069364 B2

PTL 3: WO 2011/083635 A1

PTL 4: WO 2013/088796 A1

SUMMARY OF INVENTION Technical Problem

However, for example, when an aromatic polycarbonate resin compositionis used in a light-guiding plate application, from the viewpoint that athin-walled and large light-guiding plate is obtained, molding under ahigh-temperature condition largely exceeding 300° C. is performed forimproving the flowability of the resin composition. A molded bodyobtained by such molding under a high-temperature condition is liable tocause yellowing or a reduction in light transmittance.

The problem to be solved by the present invention is to provide anaromatic polycarbonate resin molded body that has a thin-walled portion,is reduced in yellowing, and is excellent in light transmissionproperty.

Solution to Problem

The inventors of the present invention have made extensiveinvestigations, and as a result, have found that the problem can besolved by using an aromatic polycarbonate resin molded body in which thecontent of a specific component is equal to or less than a predeterminedamount. Thus, the inventors have completed the present invention.

That is, according to one embodiment of the present invention, there isprovided an aromatic polycarbonate resin molded body to be describedbelow.

<1> An aromatic polycarbonate resin molded body, which is obtained bymolding a resin molding material comprising an aromatic polycarbonateresin (A), wherein:

the molded body has a thin-walled portion having a thickness of 0.5 mmor less;

the molded body has an o-hydroxyacetophenone content of 1 ppm by mass orless and a nitrogen atom content of 15 ppm or less; and

the molded body is free of an absorption maximum in a wavelength rangeof from 500 nm to 600 nm.

<2> The aromatic polycarbonate resin molded body according to Item <1>,wherein a length in a longitudinal direction of the molded body is 60 mmor more, and a thickness of a region accounting for at least 80% of themolded body is 0.7 mm or less.

<3> The aromatic polycarbonate resin molded body according to Item <1>or <2>, wherein when a total signal intensity observed in a chemicalshift region of from 1.5 ppm or more to 1.9 ppm or less at a time ofmeasurement of a proton NMR spectrum is defined as 100, the molded bodyhas a ratio of a total signal intensity observed in a chemical shiftregion of from 6.3 ppm or more to 6.7 ppm or less of 0.15 or less.<4> The aromatic polycarbonate resin molded body according to any one ofItems <1> to <3>, wherein the resin molding material further comprises apolyether compound (b1) having a polyoxyalkylene structure.<5> The aromatic polycarbonate resin molded body according to any one ofItems <1> to <4>, wherein the resin molding material further comprisesan acid-generating compound (b2).<6> The aromatic polycarbonate resin molded body according to Item <5>,wherein the acid-generating compound (b2) comprises at least oneselected from a boronic acid anhydride and a sulfonate.<7> The aromatic polycarbonate resin molded body according to any one ofItems <4> to <6>, wherein a content of the polyether compound (b1) isfrom 0.01 part by mass to 5 parts by mass with respect to 100 parts bymass of the aromatic polycarbonate resin (A).<8> The aromatic polycarbonate resin molded body according to any one ofItems <5> to <7>, wherein a content of the acid-generating compound (b2)is from 0.0001 part by mass to 0.5 part by mass with respect to 100parts by mass of the aromatic polycarbonate resin (A).<9> The aromatic polycarbonate resin molded body according to any one ofItems <1> to <8>, wherein the aromatic polycarbonate resin (A) has aviscosity-average molecular weight (Mv) of from 10,000 to 50,000.<10> A light-guiding plate, comprising the aromatic polycarbonate resinmolded body of any one of Items <1> to <9>.

Advantageous Effects of Invention

According to the present invention, the aromatic polycarbonate resinmolded body that has a thin-walled portion having a thickness of 0.5 mmor less, is reduced in yellowing, and is excellent in light transmissionproperty can be provided.

DESCRIPTION OF EMBODIMENTS

[Aromatic Polycarbonate Resin Molded Body]

An aromatic polycarbonate resin molded body of the present invention(hereinafter referred to as “molded body of the present invention” orsimply “molded body”) is an aromatic polycarbonate resin molded body,which is obtained by molding a resin molding material containing anaromatic polycarbonate resin (A), wherein: the molded body has athin-walled portion having a thickness of 0.5 mm or less; the moldedbody has an o-hydroxyacetophenone content of 1 ppm by mass or less and anitrogen atom content of 15 ppm or less; and the molded body is free ofan absorption maximum in a wavelength range of from 500 nm to 600 nm. Inthe present invention, the phrase “has a thin-walled portion having athickness of 0.5 mm or less” means that part or the entirety of themolded body has a thickness of 0.5 mm or less.

The inventors of the present invention have found that when a resinmolding material containing an aromatic polycarbonate is molded at ahigh temperature largely exceeding 300° C. for producing a molded bodyhaving a thin-walled portion having a thickness of 0.5 mm or less, itsyellowing is particularly liable to occur and the yellowing is caused byo-hydroxyacetophenone.

o-Hydroxyacetophenone is a compound produced by, for example, thethermal decomposition of an aromatic polycarbonate resin. When thecontent of o-hydroxyacetophenone in the aromatic polycarbonate resinmolded body is more than 1 ppm by mass, remarkable yellowing of themolded body occurs to be responsible for the impairment of the externalappearance and performance of the molded body. From the viewpoint thatthe yellowing is reduced, the content of o-hydroxyacetophenone in thearomatic polycarbonate resin molded body is preferably 0.5 ppm by massor less, more preferably 0.4 ppm by mass or less, still more preferably0.3 ppm by mass or less, most preferably 0.2 ppm by mass or less.

The content of o-hydroxyacetophenone in the molded body of the presentinvention can be measured by a high-performance liquid chromatography(HPLC) method. Specifically, the content can be measured by a methoddescribed in Examples.

A method of reducing the content of o-hydroxyacetophenone in the moldedbody of the present invention is, for example, a method involvingadding, to the polycarbonate resin molding material to be used for theproduction of the aromatic polycarbonate resin molded body of thepresent invention, at least one compound selected from a polyethercompound (b1) having a polyoxyalkylene structure and an acid-generatingcompound (b2). The compounds are described later.

In addition, when a large amount of a basic compound is present in thearomatic polycarbonate resin molded body of the present invention, thecompound tends to act on o-hydroxyacetophenone described in theforegoing to accelerate the yellowing of the molded body, and when themolded body of the present invention is a light-guiding plate, thecompound is responsible for a reduction in its light-guidingperformance. Among the basic compounds, an amine compound reacts witho-hydroxyacetophenone to form an imine and the imine is assumed toaccelerate the yellowing. From the viewpoint, a nitrogen atom content inthe molded body of the present invention is 15 ppm or less, preferably10 ppm or less, more preferably 8 ppm or less, still more preferably 5ppm or less.

When the basic compound, such as the amine compound, is incorporatedinto a polycarbonate resin, the content of the basic compound in themolded body of the present invention can be reduced by, for example,increasing the number of times of the washing of the polycarbonate resinor a stirring power at the time of the washing.

The nitrogen atom content in the molded body of the present inventioncan be measured by a chemiluminescence method, and specifically, thecontent can be measured by a method described in Examples.

In addition, the aromatic polycarbonate resin molded body of the presentinvention is free of an absorption maximum in the wavelength range offrom 500 nm to 600 nm. It has been known that an aromatic polycarbonateresin molded body is blended with, for example, a colorant (bluingagent) having an absorption maximum in the wavelength range of from 500nm to 600 nm for offsetting coloring in a yellow color. In the method,however, when the aromatic polycarbonate resin molding material ismolded under a high-temperature condition largely exceeding 300° C. forthin-wall molding, a molded body to be obtained yellows owing to thedeterioration or volatilization of the coloring agent. In the presentinvention, a molded body reduced in yellowing and excellent in lighttransmission property can be obtained without the blending of suchcoloring agent or the like.

In the present invention, the phrase “free of an absorption maximum inthe wavelength range of from 500 nm to 600 nm” means that when 6 g of anaromatic polycarbonate resin molded body is dissolved in 50 mL ofmethylene chloride, and the absorption spectrum of the solution ismeasured with a quartz cell having an optical path length of 5 cm and aUV-visible spectrophotometer by a transmission method, no absorptionmaximum is present in the wavelength range of from 500 nm to 600 nm. Inthe present invention, it is preferred that absorption except absorptionderived from the aromatic polycarbonate resin be absent in thewavelength range of from 500 nm to 600 nm. The aromatic polycarbonateresin molded body can be specifically evaluated for the presence orabsence of an absorption maximum in the wavelength range of from 500 nmto 600 nm by a method described in Examples.

Further, in the aromatic polycarbonate resin molded body of the presentinvention, when a total signal intensity observed in a chemical shiftregion of from 1.5 ppm or more to 1.9 ppm or less at a time ofmeasurement of a proton NMR spectrum is defined as 100, a ratio of atotal signal intensity observed in a chemical shift region of from 6.3ppm or more to 6.7 ppm or less is preferably 0.15 or less, morepreferably 0.10 or less. When the signal intensity ratio is 0.15 orless, an aromatic polycarbonate resin molded body additionally reducedin yellowing and additionally excellent in light transmission propertycan be obtained. It should be noted that a signal observed in thechemical shift region of from 1.5 ppm or more to 1.9 ppm or less isderived mainly from a proton of the isopropylidene group of bisphenol Aserving as the main structure of the aromatic polycarbonate resin to beused in the molded body of the present invention.

The signal intensity ratio can be determined by measuring a proton NMRspectrum. The proton NMR spectrum can be specifically measured by amethod described in Examples.

The thickness of the thin-walled portion of the aromatic polycarbonateresin molded body of the present invention is 0.5 mm or less, preferably0.45 mm or less, more preferably 0.4 mm or less, still more preferably0.35 mm or less.

Here, as the thickness of the thinnest portion of the aromaticpolycarbonate resin molded body of the present invention becomesthinner, the effects of the present invention can be exhibited to alarger extent, but a lower limit for the thickness of the thinnestportion can be set to, for example, 0.1 mm or more, 0.15 mm or more, or0.2 mm or more.

The shape of the molded body of the present invention is notparticularly limited as long as at least part of the molded body has thethin-walled portion having a thickness of 0.5 mm or less, but a moldedbody having a plate shape, such as a flat plate, or a curved plate orprism transfer plate having a lens effect, is preferred from theviewpoint of its application to a light-guiding plate or the like. It ispreferred that a length in the longitudinal direction of the molded bodyto be applied to the light-guiding plate or the like be 60 mm or more,and the thickness of a region accounting for at least 80% of the moldedbody be 0.7 mm or less, it is more preferred that the length in thelongitudinal direction be 65 mm or more, and the thickness of the regionaccounting for at least 80% of the molded body be 0.5 mm or less, it isstill more preferred that the length in the longitudinal direction be 70mm or more, and the thickness of the region accounting for at least 80%of the molded body be 0.45 mm or less, and it is still further morepreferred that the length in the longitudinal direction be 70 mm ormore, and the thickness of the region accounting for at least 80% of themolded body be 0.4 mm or less.

It should be noted that an upper limit for the length in thelongitudinal direction is not particularly limited, but can be set to,for example, 300 mm or less.

In addition, a lower limit for the thickness of the region accountingfor at least 80% of the molded body is not particularly limited, but canbe set to, for example, 0.1 mm or more, 0.15 mm or more, or 0.2 mm ormore. It should be noted that in the present invention, the phrase “thethickness of the region accounting for at least 80% of the molded bodyis 0.7 mm or less” means that when the molded body has, for example, aplate shape, a thickness is 0.7 mm or less in a region accounting for atleast 80% of the entire area of the plate-shaped molded body.

[Polycarbonate Resin Molding Material]

The aromatic polycarbonate resin molded body of the present invention isobtained by molding the resin molding material containing the aromaticpolycarbonate resin (A). That is, the kinds of the respective componentsto be used in the aromatic polycarbonate resin molded body of thepresent invention and preferred contents thereof are the same as thekinds of respective components to be used in a polycarbonate resinmolding material to be described below and preferred contents thereof.

(Aromatic Polycarbonate Resin (A))

The polycarbonate resin molding material to be used in the presentinvention contains the aromatic polycarbonate resin (A). A resinproduced by a known method can be used as the aromatic polycarbonateresin (A) without any particular limitation.

For example, a resin produced from a dihydric phenol and a carbonateprecursor by a solution method (interfacial polycondensation method) ora melting method (ester exchange method), i.e., a resin produced by theinterfacial polycondensation method involving causing the dihydricphenol and phosgene to react with each other in the presence of an endterminator, or by causing the dihydric phenol and diphenyl carbonate orthe like to react with each other in the presence of the end terminatoraccording to the ester exchange method or the like can be used.

Examples of the dihydric phenol can include various dihydric phenols, inparticular, 2,2-bis(4-hydroxyphenyl)propane [bisphenol A],bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane,2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 4,4′-dihydroxydiphenyl, abis(4-hydroxyphenyl)cycloalkane, bis(4-hydroxyphenyl) oxide,bis(4-hydroxyphenyl) sulfide, bis(4-hydroxyphenyl) sulfone,bis(4-hydroxyphenyl) sulfoxide, and bis(4-hydroxyphenyl) ketone. Inaddition, examples thereof can also include hydroquinone, resorcin, andcatechol. One kind of those dihydric phenols may be used alone, or twoor more kinds thereof may be used in combination. Among them,bis(hydroxyphenyl)alkane-based phenols are preferred, and bisphenol A isparticularly suitable. By using bisphenol A as the dihydric phenol, apolycarbonate resin having a bisphenol A structure can be obtained.

The carbonate precursor is, for example, a carbonyl halide, a carbonylester, or a haloformate, and is specifically phosgene, a dihaloformateof a dihydric phenol, diphenyl carbonate, dimethyl carbonate, diethylcarbonate, or the like.

It should be noted that the component (A) in the present invention mayhave a branched structure, and a branching agent may be, for example,1,1,1-tris(4-hydroxyphenyl)-ethane,α,α′,α″-tris(4-hydroxyphenyl)-1,3,5-triisopropylbenzene, phloroglucin,trimellitic acid, or 1,3-bis(o-cresol).

A monovalent carboxylic acid or a derivative thereof or a monohydricphenol can be used as the end terminator. Examples thereof can includep-tert-butyl-phenol, p-phenylphenol, p-cumylphenol,p-perfluorononylphenol, p-(perfluorononylphenyl)phenol,p-(perfluorohexylphenyl)phenol, p-tert-perfluorobutylphenol,1-(p-hydroxybenzyl)-perfluorodecane,p-[2-(1H,1H-perfluorotridodecyloxy)-1,1,1,3,3,3-hexafluoropropyl]phenol,3,5-bis(perfluorohexyloxycarbonyl)phenol, perfluorododecylp-hydroxybenzoate, p-(1H,1H-perfluorooctyloxy)phenol,2H,2H,9H-perfluorononanoic acid, and 1,1,1,3,3,3-hexafluoro-2-propanol.

It is preferred that the aromatic polycarbonate resin (A) include apolycarbonate resin including, in a main chain thereof, a repeating unitrepresented by the following formula (I).

In the formula, R^(A1) and R^(A2) each independently represent an alkylgroup or alkoxy group having 1 to 6 carbon atoms, X represents a singlebond, an alkylene group having 1 to 8 carbon atoms, an alkylidene grouphaving 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbonatoms, a cycloalkylidene group having 5 to 15 carbon atoms, —S—, —SO—,—SO₂—, —O—, or —CO—, and a and b each independently represent an integerof from 0 to 4.

Examples of the alkyl group represented by each of R^(A1) and R^(A2)include a methyl group, an ethyl group, a n-propyl group, an isopropylgroup, various butyl groups (the term “various” means that a lineargroup and various branched groups are included, and the same holds truefor the following), various pentyl groups, and various hexyl groups. Anexample of the alkoxy group represented by each of R^(A1) and R^(A2) isan alkoxy group whose alkyl group moiety is the alkyl group describedabove.

R^(A1) and R^(A2) each preferably represent an alkyl group having 1 to 4carbon atoms or an alkoxy group having 1 to 4 carbon atoms.

Examples of the alkylene group represented by X include a methylenegroup, an ethylene group, a trimethylene group, a tetramethylene group,and a hexamethylene group. Among them, an alkylene group having 1 to 5carbon atoms is preferred. Examples of the alkylidene group representedby X include an ethylidene group and an isopropylidene group. Examplesof the cycloalkylene group represented by X include a cyclopentanediylgroup, a cyclohexanediyl group, and a cyclooctanediyl group. Among them,a cycloalkylene group having 5 to 10 carbon atoms is preferred. Examplesof the cycloalkylidene group represented by X include a cyclohexylidenegroup, a 3,5,5-trimethylcyclohexylidene group, and a 2-adamantylidenegroup. Among them, a cycloalkylidene group having 5 to 10 carbon atomsis preferred, and a cycloalkylidene group having 5 to 8 carbon atoms ismore preferred.

a and b each independently represent an integer of from 0 to 4,preferably from 0 to 2, more preferably 0 or 1.

In the present invention, the aromatic polycarbonate resin (A)preferably contains a polycarbonate resin having a bisphenol A structurefrom the viewpoints of, for example, the transparency, mechanicalcharacteristics, and thermal characteristics of a molded body to beobtained. The polycarbonate resin having a bisphenol A structure isspecifically, for example, such a resin that X in the formula (I)represents an isopropylidene group. The content of the polycarbonateresin having a bisphenol A structure in the aromatic polycarbonate resin(A) is preferably from 50 mass % to 100 mass %, more preferably from 75mass % to 100 mass %, still more preferably from 85 mass % to 100 mass%.

In the present invention, the viscosity-average molecular weight (Mv) ofthe aromatic polycarbonate resin (A) is generally from about 10,000 toabout 50,000, preferably from 13,000 to 35,000, more preferably from14,000 to 20,000.

In the present invention, the viscosity-average molecular weight (Mv) iscalculated from the following equation by using a limiting viscosity [η]determined through the measurement of the viscosity of a methylenechloride solution at 20° C. with an Ubbelohde-type viscometer.[η]=1.23×10⁻⁵ Mv ^(0.83)

The polycarbonate resin molding material to be used in the presentinvention preferably contains at least one compound selected from thepolyether compound (b1) having a polyoxyalkylene structure and theacid-generating compound (b2). Thus, even when the material is moldedunder a high-temperature condition largely exceeding 300° C., anaromatic polycarbonate resin molded body reduced in yellowing andexcellent in light transmission property can be obtained. Although thereason why the effect is obtained is uncertain, the compound is assumedto suppress the production of o-hydroxyacetophenone described in theforegoing.

(Polyether Compound (b1) Having Polyoxyalkylene Structure)

The polyether compound (b1) having a polyoxyalkylene structure to beused in the present invention preferably has a polyoxyalkylene structurerepresented by (R^(b1)O)_(m) and a polyoxyalkylene structure representedby (R^(b2)O)_(n). In the formulae, R^(b1) and R^(b2) each independentlyrepresent an alkylene group having 1 or more carbon atoms, and m+n is 5or more and less than 300, preferably from 10 to 200, more preferablyfrom 20 to 100.

Examples of the alkylene group represented by each of R^(b1) and R^(b2)include a methylene group, an ethylene group, a trimethylene group, apropylene group, a tetramethylene group, and a hexamethylene group.Among them, an alkylene group having 1 to 5 carbon atoms is preferred.

In m R^(b1)O groups, a plurality of R^(b1)'s may represent alkylenegroups identical to each other, or may represent alkylene groupsdifferent from each other in number of carbon atoms. That is, apolyoxyalkylene group represented by (R^(b1)O)_(m) is not limited to agroup having a single oxyalkylene unit as a repeating unit, such as apolyoxyethylene group or a polyoxypropylene group, and may be a grouphaving a plurality of oxyalkylene units different from each other innumber of carbon atoms, such as an oxyethylene unit and an oxypropyleneunit, as repeating units.

In addition, the same description as that of R^(b1) holds true forR^(b2), and in n R^(b2)O groups, a plurality of R^(b2)'s may representalkylene groups identical to each other, or may represent alkylenegroups different from each other in number of carbon atoms.

In addition, the polyether compound (b1) is preferably at least oneselected from a compound (b1-1) represented by the following formula(II), an alkylene oxide adduct of a polyhydric alcohol and an esterthereof (b1-2), and a cyclic polyether compound (b1-3):R^(b3)O—(R^(b1)O)_(m)-A-(R^(b2)O)_(n)—R^(b4)  (II)wherein R^(b1) and R^(b2) each independently represent an alkylene grouphaving 1 or more carbon atoms, and m+n is 5 or more and less than 300,R^(b3) and R^(b4) each independently represent a hydrogen atom, ahydrocarbon group having 1 to 30 carbon atoms, an alkanoyl group having1 to 30 carbon atoms, an alkenoyl group having 2 to 30 carbon atoms, ora glycidyl group, and A represents a single bond or a divalent organicgroup.

The alkylene group represented by each of R^(b1) and R^(b2) is asdescribed above. The polyoxyalkylene structure represented by(R^(b1)O)_(m), and the polyoxyalkylene structure represented by(R^(b2)O)_(n) are also as described above.

Examples of the hydrocarbon group having 1 to 30 carbon atomsrepresented by each of R^(b3) and R^(b4) include an alkyl group having 1to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, anaryl group having 6 to 30 carbon atoms, and an aralkyl group having 7 to30 carbon atoms.

Each of the alkyl group and the alkenyl group may be linear, branched,or cyclic. Examples thereof include a methyl group, an ethyl group, an-propyl group, an isopropyl group, various butyl groups, various pentylgroups, various hexyl groups, various octyl groups, a cyclopentyl group,a cyclohexyl group, an allyl group, a propenyl group, various butenylgroups, various hexenyl groups, various octenyl groups, a cyclopentenylgroup, and a cyclohexenyl group. Examples of the aryl group include aphenyl group, a tolyl group, and a xylyl group. Examples of the aralkylgroup include a benzyl group, a phenethyl group, and a methylbenzylgroup.

The alkanoyl group having 1 to 30 carbon atoms represented by each ofR^(b3) and R^(b4) may be linear or branched, and examples thereofinclude a methanoyl group, an ethanoyl group, a n-propanoyl group, anisopropanoyl group, a n-butanoyl group, a t-butanoyl group, a n-hexanoylgroup, a n-octanoyl group, a n-decanoyl group, a n-dodecanoyl group, anda benzoyl group. Among them, an alkanoyl group having 1 to 20 carbonatoms is preferred from the viewpoints of the compatibility, heatstability, and ease of production of the composition.

The alkenoyl group having 2 to 30 carbon atoms represented by each ofR^(b3) and R^(b4) may be linear or branched, and examples thereofinclude an ethenoyl group, a n-propenoyl group, an isopropenoyl group, an-butenoyl group, a t-butenoyl group, a n-hexenoyl group, a n-octenoylgroup, a n-decenoyl group, and a n-dodecenoyl group. Among them, analkenoyl group having 2 to 10 carbon atoms is preferred, and an alkenoylgroup having 2 to 6 carbon atoms is more preferred from the viewpointthat the molecular weight of the composition is reduced, from theviewpoints of its compatibility and solubility, and from the viewpointof its ease of production.

The divalent organic group represented by A is, for example, a grouprepresented by the following formula (a).

Specific examples of the compound (b1-1) represented by the formula (II)include polyethylene glycol, polypropylene glycol, polytetramethyleneglycol, polyoxytetramethylene-polyoxyethylene glycol, polyoxyethylenemonomethyl ether, polyoxyethylene dimethyl ether,polyoxyethylene-bisphenol A ether, polyoxypropylene-bisphenol A ether,polyoxyethylene-polyoxypropylene-bisphenol A ether, polyethyleneglycol-allyl ether, polyethylene glycol-diallyl ether, polypropyleneglycol-allyl ether, polypropylene glycol-diallyl ether, polyethyleneglycol-polypropylene glycol-allyl ether, polyethylene glycoldimethacrylate, polypropylene glycol dimethacrylate, and polypropyleneglycol distearate. Those compounds are available as commercial products,and for example, “UNIOX (trademark)”, “UNIOL (trademark)”, “UNILUB(trademark)”, “UNISAFE (trademark)”, “POLYCERIN (trademark)”, or “EPIOL(trademark)”, which is manufactured by NOF Corporation, can be used.

In the alkylene oxide adduct of a polyhydric alcohol and the esterthereof (b1-2), examples of the polyhydric alcohol include glycerin,diglyceryl ether, and sorbitol.

Specific examples of the cyclic polyether compound (b1-3) include18-crown-6 and dibenzo-18-crown-6.

The number-average molecular weight of the polyether compound (b1),which is not particularly limited, is preferably from 200 to 10,000,more preferably from 500 to 8,000, still more preferably from 1,000 to5,000.

One kind of the polyether compounds (b1) can be used alone, or two ormore kinds thereof can be used in combination.

From the viewpoint that the production of o-hydroxyacetophenone issuppressed, and hence even when the polycarbonate resin molding materialto be used in the present invention is molded under a high-temperaturecondition largely exceeding 300° C., an aromatic polycarbonate resinmolded body reduced in yellowing and excellent in light transmissionproperty is obtained, the content of the polyether compound (b1) in thematerial is preferably from 0.01 part by mass to 5 parts by mass, morepreferably from 0.02 part by mass to 2 parts by mass, still morepreferably from 0.03 part by mass to 1 part by mass with respect to 100parts by mass of the aromatic polycarbonate resin (A).

(Acid-Generating Compound (b2))

Examples of the acid-generating compound (b2) to be used in the presentinvention include anhydrides of acidic compounds, such as a carboxylicacid, a sulfonic acid, and a boronic acid, and esters of the acidiccompounds. From the viewpoint that the production ofo-hydroxyacetophenone is suppressed, and hence even when thepolycarbonate resin molding material is molded under a high-temperaturecondition largely exceeding 300° C., an aromatic polycarbonate resinmolded body reduced in yellowing and excellent in light transmissionproperty is obtained, the acid-generating compound (b2) is preferably atleast one selected from a boronic acid anhydride and a sulfonate, morepreferably at least one selected from a boronic acid anhydride having anaromatic ring and a sulfonate having an aromatic ring.

The boronic acid anhydride is preferably an arylboronic acid anhydridethat may have a substituent on an aromatic ring thereof, and examplesthereof include phenylboronic acid anhydride, 4-methylphenylboronic acidanhydride, 4-methoxyphenylboronic acid anhydride,4-tert-butoxyphenylboronic acid anhydride, and 4-fluorophenylboronicacid anhydride. From the viewpoint of the heat stability of thepolycarbonate resin molding material, at least one selected fromphenylboronic acid anhydride and 4-methoxyphenylboronic acid anhydrideis more preferred.

The sulfonate is preferably an alkyl ester of p-toluenesulfonic acid.The alkyl ester preferably has 1 to 20 carbon atoms, and more preferablyhas 1 to 12 carbon atoms, and examples thereof include butylp-toluenesulfonate, octyl p-toluenesulfonate, and dodecylp-toluenesulfonate. From the viewpoints of the ease with which theacid-generating compound generates an acid and the ease with which adecomposition product thereof volatilizes, at least one selected frombutyl p-toluenesulfonate and octyl p-toluenesulfonate is more preferred.

One kind of the acid-generating compounds (b2) can be used alone, or twoor more kinds thereof can be used in combination.

From the viewpoint that the production of o-hydroxyacetophenone issuppressed, and hence even when the polycarbonate resin molding materialis molded under a high-temperature condition largely exceeding 300° C.,an aromatic polycarbonate resin molded body reduced in yellowing andexcellent in light transmission property is obtained, the content of theacid-generating compound (b2) in the material is preferably from 0.0001part by mass to 0.5 part by mass with respect to 100 parts by mass ofthe aromatic polycarbonate resin (A).

In addition, from the same viewpoint as that described above, when theacid-generating compound (b2) is a boronic acid anhydride, its contentis more preferably from 0.01 part by mass to 0.5 part by mass, stillmore preferably from 0.02 part by mass to 0.5 part by mass with respectto 100 parts by mass of the aromatic polycarbonate resin (A). On theother hand, when the acid-generating compound (b2) is a sulfonate, itscontent is more preferably from 0.0001 part by mass to 0.1 part by mass,still more preferably from 0.0001 part by mass to 0.01 part by mass withrespect to 100 parts by mass of the aromatic polycarbonate resin (A).

It should be noted that in the polycarbonate resin molding material tobe used in the present invention, the polyether compound (b1) and theacid-generating compound (b2) may be used in combination. In that case,the respective preferred contents of the polyether compound (b1) and theacid-generating compound (b2) are the same as those described in theforegoing.

(Antioxidant (C))

The polycarbonate resin molding material to be used in the presentinvention preferably further contains an antioxidant (C). When thematerial contains the antioxidant (C), its oxidation deterioration isprevented even when molded under a high-temperature condition, and hencean aromatic polycarbonate resin molded body reduced in yellowing andexcellent in light transmission property can be obtained.

Examples of the antioxidant (C) include a phosphorus-based antioxidantand a hindered phenol-based antioxidant. From the viewpoint of thesuppression of the oxidation deterioration of the polycarbonate resinmolding material at the time of its high-temperature molding, aphosphorus-based antioxidant is preferably used and a phosphorus-basedantioxidant having an aryl group is more preferred.

Further, from the viewpoints that the phosphorus-based antioxidanthaving an aryl group is reduced in thermal decomposition even in moldingunder a high-temperature condition, that the antioxidant can suppressthe oxidation deterioration of the polycarbonate resin molding material,and that a molded body reduced in the occurrence of yellowing and areduction in light transmittance is obtained, the antioxidant ispreferably such a compound that the amount of a compound having a phenolstructure produced by the decomposition of the compound 1,500 hoursafter its standing under the conditions of 40° C. and a humidity of 90%is preferably 5 mass % or less, more preferably 3 mass % or less, stillmore preferably 1 mass % or less, particularly preferably 0.5 mass % orless. That is, the phosphorus-based antioxidant having an aryl group tobe preferably used in the present invention is excellent in hydrolysisresistance and is reduced in production amount of the compound having aphenol structure. It should be noted that the amount of the compoundhaving a phenol structure is determined with a gas chromatograph.

The antioxidant (C) to be used in the present invention is preferably aphosphorus-based antioxidant having an aryl group and a phosphitestructure, more preferably a pentaerythritol diphosphite compoundrepresented by the following formula (III).

In the formula, Y¹ to Y⁴ each independently represent a hydrocarbongroup having 6 or more carbon atoms, and preferably each independentlyrepresent a substituted or unsubstituted cumyl group, a substituted orunsubstituted phenyl group, a substituted or unsubstituted naphthylgroup, or a substituted or unsubstituted biphenyl group.

The antioxidant (C) to be used in the present invention is morepreferably a pentaerythritol diphosphite compound represented by thefollowing formula (III-1).

In the formula, R^(C1) to R^(C8) each independently represent an alkylgroup or an alkenyl group, R^(C1) and R^(C2), R^(C3) and R^(C4), R^(C5)and R^(C6), or R^(C7) and R^(C8) may be bonded to each other to form aring, R^(C9) to R^(C12) each independently represent a hydrogen atom oran alkyl group, m1 to m4 each independently represent an integer of from0 to 5, and Z¹ to Z⁴ each independently represent a single bond or acarbon atom, and when Z¹ to Z⁴ each represent a single bond, R^(C1) toR^(C8) are excluded from the formula (III-1).

The pentaerythritol diphosphite compound represented by the formula(III) or (III-1) can be obtained by adding a chlorine-based solvent tophosphorus trichloride and pentaerythritol to provide pentaerythritoldichlorophosphite, and then heating and mixing the contents in thepresence of an aromatic solvent and an organic nitrogen-containing basiccompound (see, for example, JP 2004-018406 A).

Among the pentaerythritol diphosphite compounds each represented by theformula (III) or (III-1), bis(2,4-dicumylphenyl)pentaerythritoldiphosphite represented by the following formula (III-2) is particularlysuitable because the compound can satisfactorily impart heat resistanceand hydrolysis resistance to the polycarbonate resin molding material,and is easily available. The compound is available as a commercialproduct, and for example, “Doverphos (trademark) S-9228PC” manufacturedby Dover Chemical can be used.

One kind of the antioxidants (C) can be used alone, or two or more kindsthereof can be used in combination.

The content of the antioxidant (C) in the polycarbonate resin moldingmaterial to be used in the present invention is preferably from 0.005part by mass to 1 part by mass, more preferably from 0.01 part by massto 0.8 part by mass, still more preferably from 0.03 part by mass to0.25 part by mass with respect to 100 parts by mass of the aromaticpolycarbonate resin (A) from the viewpoint of the suppression of itsoxidation deterioration.

(Additive)

In addition to the components described above, a polyorganosiloxane orthe like can be appropriately added to the polycarbonate resin moldingmaterial to be used in the present invention.

The polyorganosiloxane is preferably a compound having one or more kindsof functional groups such as an alkoxy group, an aryloxy group, apolyoxyalkylene group, a carboxyl group, a silanol group, an aminogroup, a mercapto group, an epoxy group, and a vinyl group.

The addition amount of the polyorganosiloxane is preferably from 0.01part by mass to 0.15 part by mass, more preferably from 0.02 part bymass to 0.15 part by mass, still more preferably from 0.05 part by massto 0.1 part by mass with respect to 100 parts by mass of the aromaticpolycarbonate resin (A). When the addition amount falls within the rangeof from 0.01 part by mass to 0.15 part by mass, the polyorganosiloxanecan concert with any other component to improve the releasability of themolding material. Further, even under a high-temperature moldingcondition largely exceeding 300° C., in particular, a continuous moldingcondition, the occurrence of silver and the amount of a mold deposit canbe significantly reduced.

The viscosity of the polyorganosiloxane at 25° C. is preferably 10 mm²/sor more from the viewpoint of a lubricating effect serving as thereleasability, and is preferably 200 mm²/s or less from the viewpoint ofits dispersibility in the polycarbonate resin. From the viewpoints, theviscosity of the polyorganosiloxane falls within the range of morepreferably from 20 mm²/s to 150 mm²/s, still more preferably from 40mm²/s to 120 mm²/s.

A difference between the refractive index of the polyorganosiloxane andthe refractive index of the polycarbonate resin is preferably made assmall as possible in order that the transparency of the polycarbonateresin molding material may not be reduced upon addition of thepolyorganosiloxane thereto. The refractive index of thepolyorganosiloxane is preferably 1.45 or more, more preferably 1.50 ormore, still more preferably 1.52 or more because the refractive index ofthe aromatic polycarbonate resin (A) is 1.58.

[Method of Producing Polycarbonate Resin Molding Material]

A method of producing the polycarbonate resin molding material to beused in the present invention is not particularly limited.

For example, the aromatic polycarbonate resin (A), and as required, thecompounds (b1) and (b2), the antioxidant (C), and various additives aremixed, and the mixture is melted and kneaded. The melting and kneadingcan be performed by a typically used method, for example, a method usinga ribbon blender, a Henschel mixer, a Banbury mixer, a drum tumbler, asingle-screw extruder, a double-screw extruder, a co-kneader, amultiple-screw extruder, or the like. In normal cases, a heatingtemperature at the time of the melting and kneading is appropriatelyselected from the range of from about 220° C. to about 300° C.

(Method of Producing Aromatic Polycarbonate Resin Molded Body)

The aromatic polycarbonate resin molded body of the present invention isobtained by molding the polycarbonate resin molding material.Specifically, the aromatic polycarbonate resin molded body can beproduced by using the melt-kneaded product of the polycarbonate resinmolding material or the resultant resin pellet as a raw material throughthe application of a known molding method, such as a hollow moldingmethod, an injection molding method, an injection compression moldingmethod, an extrusion molding method, a vacuum molding method, a blowmolding method, a press molding method, an air-pressure molding method,an expansion molding method, a heat bending molding method, acompression molding method, a calender molding method, or a rotationalmolding method.

A molding method requiring the molding material to have highflowability, such as an injection molding method, is preferably usedbecause the aromatic polycarbonate resin molded body of the presentinvention has a thin-walled portion having a thickness of 0.5 mm orless. A condition for the molding is not particularly limited, but themolding is preferably performed at 300° C. or more because the moldedbody has the thin-walled portion. Thus, the optical distortion of themolded body to be obtained can be reduced, and a fine processingportion, such as a prism portion, can be satisfactorily transferred. Themolding temperature is more preferably from 310° C. to 360° C.

[Light-Guiding Plate]

The aromatic polycarbonate resin molded body of the present invention isuseful in an optical molded article application, especially alight-guiding plate application.

A light-guiding plate formed of the aromatic polycarbonate resin moldedbody of the present invention is not particularly limited as long as theplate has a thin-walled portion having a thickness of 0.5 mm or less,and the plate may be a flat plate, or may be a curved plate or prismtransfer plate having a lens effect. A preferred size and a preferredthickness of the light-guiding plate are the same as those of the moldedbody. A method of molding the light-guiding plate is also notparticularly limited, and needs only to be appropriately selected. Apreferred method of producing the light-guiding plate is also the sameas the method of producing the molded body.

EXAMPLES

The present invention is described by way of Examples but the presentinvention is not limited to these Examples.

Production examples of bisphenol A polycarbonate resins (PC-1) to (PC-3)used in Examples and Comparative Examples are described below.

Production Example 1 Production of Bisphenol A Polycarbonate Resin(PC-1)

4 kg of “TARFLON FN1500” (manufactured by Idemitsu Kosan Co., Ltd.,bisphenol A polycarbonate resin, viscosity-average molecular weight:14,500) was dissolved in 25 L of methylene chloride, and in a washingmachine with a baffle board and a stirring blade, the solution wasvigorously stirred and mixed with 5 L of 0.03 mol/L aqueous sodiumhydroxide, 5 L of 0.2 mol/L hydrochloric acid, and 5 L of pure water inthe stated order, followed by standing separation. After it had beenconfirmed that the electric conductivity of an aqueous phase had become0.05 ρS/m or less, pure water was further added to the resultant, andthe contents were stirred and mixed once. A solution of thepolycarbonate resin in dichloromethane obtained by the washing wasconcentrated and pulverized, and the resultant flake was dried at 100°C. under reduced pressure to provide the bisphenol A polycarbonate resin(PC-1).

Production Example 2 Production of Bisphenol A Polycarbonate Resin(PC-2)

(1) Polycarbonate Oligomer Synthesis Step

2,000 parts per million by mass of sodium dithionite with respect tobisphenol A (hereinafter sometimes abbreviated as “BPA”) to be dissolvedlater was added to 5.6 mass % aqueous sodium hydroxide, and bisphenol Awas dissolved in the mixture so that a bisphenol A concentration became13.5 mass %. Thus, a solution of bisphenol A in aqueous sodium hydroxidewas prepared. 40 L/hr of the solution of bisphenol A in aqueous sodiumhydroxide, 15 L/hr of methylene chloride, and 4.0 kg/hr of phosgene werecontinuously passed through a tubular reactor having an inner diameterof 6 mm and a tube length of 30 m. The tubular reactor had a jacketportion, and the temperature of a reaction liquid was kept at 40° C. orless by passing cooling water through the jacket.

The reaction liquid that had exited the tubular reactor was continuouslyintroduced into a baffled tank reactor having an internal volume of 40L, the reactor including a sweptback blade, and 2.8 L/hr of the solutionof bisphenol A in aqueous sodium hydroxide, 0.07 L/hr of 25 mass %aqueous sodium hydroxide, 17 L/hr of water, and 0.64 L/hr of a 1 mass %aqueous solution of triethylamine were further added to the liquid toperform a reaction.

The reaction liquid overflowing the tank reactor was continuouslyextracted, and an aqueous phase was separated and removed by leaving theliquid at rest, followed by the collection of a methylene chloridephase. The resultant polycarbonate oligomer had a concentration of 325g/L and a chloroformate group concentration of 0.77 mol/L.

(2) Polycarbonate Polymerization Step

After the temperature of the cooling solvent of a 50-liter tank reactorincluding a baffle board, a paddle-type stirring blade, and a coolingjacket had become 20° C. or less, 15 L of the oligomer solution, 8.9 Lof methylene chloride, 119 g of p-tert-butylphenol, 0.7 mL oftriethylamine, and a solution of BPA in aqueous sodium hydroxide(obtained by dissolving, in an aqueous solution obtained by dissolving647 g of NaOH and 2,000 ppm by mass of sodium dithionite with respect toBPA to be dissolved later in 9.5 L of water, 1,185 g of BPA) were addedto perform a polymerization reaction for 30 minutes. After that, 0.8 mLof triethylamine was added to the resultant and the mixture was stirredfor 30 minutes.

15 L of methylene chloride was added to the mixture for dilution, andthen the diluted mixture was separated into an organic phase containinga polycarbonate resin, and an aqueous phase containing excess amounts ofBPA and NaOH, followed by the isolation of the organic phase. Theresultant solution of the polycarbonate resin in methylene chloride wassequentially washed with 0.03 mol/L aqueous NaOH and 0.2 mol/Lhydrochloric acid in amounts of 15 vol % each with respect to thesolution, and then washing with pure water was repeated until anelectric conductivity in an aqueous phase after the washing became 0.05lpS/m or less. A solution of the polycarbonate resin in dichloromethaneobtained by the washing was concentrated and pulverized, and theresultant flake was dried at 100° C. under reduced pressure to providethe bisphenol A polycarbonate resin (PC-2).

Production Example 3 Production of Bisphenol A Polycarbonate Resin(PC-3)

The bisphenol A polycarbonate resin (PC-3) was obtained in the samemanner as in Production Example 2 except that in the polycarbonatepolymerization step, after the temperature of the cooling solvent hadbecome 30° C. or less, 1.5 mL of triethylamine was added in one portioninstead of the addition of triethylamine in portions, and apolymerization reaction was performed for 60 minutes.

Examples 1 to 11 and Comparative Examples 1 to 5

After respective components had been mixed at ratios shown in Table 1,the mixture was melted and kneaded with a vented single screw extruderhaving a screw diameter of 40 mm (“VS-40” manufactured by TanabePlastics Machinery Co., Ltd.) at a cylinder temperature of 250° C., andthe melt-kneaded product was extruded to provide a resin pellet(polycarbonate resin molding material). The resin pellet was dried at110° C. for 5 hours, and was then molded into a flat plate-shaped moldedbody measuring 50 mm by 80 mm by 0.3 mm thick with an injection moldingmachine “NISSEI ES 1000” (manufactured by Nissei Plastic Industrial Co.,Ltd., clamping force: 80 t) at a cylinder temperature of 360° C. and adie temperature of 80° C. for a cycle time of 20 seconds. Themeasurement of the content of o-hydroxyacetophenone and signal analysisby proton NMR were performed by using the molded body.

It should be noted that the components used in Examples and ComparativeExamples, and the aromatic polycarbonate resin molded bodies obtained inExamples and Comparative Examples were subjected to various evaluationsby the following methods.

[Measurement of Viscosity-Average Molecular Weight (Mv)]

A viscosity-average molecular weight was calculated from the followingequation after the determination of a limiting viscosity [η] through themeasurement of the viscosity of a methylene chloride solution at 20° C.with an Ubbelohde-type viscometer.[η]=1.23×10⁻⁵ Mv ^(0.83)[Hydrolysis Resistance Test of Phosphorus-Based Antioxidant]

A phosphorus-based antioxidant was left to stand under the conditions of40° C. and a humidity of 90% for 1,500 hours. After that, the mass of acompound having a phenol structure produced by the decomposition of thephosphorus-based antioxidant was determined with a gas chromatographapparatus “GC-2014” manufactured by Shimadzu Corporation, and the ratioof the compound to the phosphorus-based antioxidant was measured.

[Measurement of Absorption Spectrum]

6 g of each of the molded bodies obtained in Examples and ComparativeExamples was dissolved in 50 mL of methylene chloride, and theabsorption spectrum of the solution in the wavelength range of from 350nm to 780 nm was measured with a quartz cell having an optical pathlength of 5 cm and a UV-visible spectrophotometer “UV-2450”(manufactured by Shimadzu Corporation). A spectral difference spectrumwas measured by using a solution obtained by similarly dissolving 6 g ofthe aromatic polycarbonate resin used in each of Examples andComparative Examples in methylene chloride on a reference side, and thepresence or absence of an absorption maximum in the wavelength range offrom 500 nm to 600 nm was confirmed.

It should be noted that in each of Examples 1 to 11, and ComparativeExamples 1 to 3 and 5, no absorption was observed in the wavelengthrange of from 500 nm to 600 nm.

[Measurement of Content of o-Hydroxyacetophenone]

Each of the molded bodies obtained in Examples and Comparative Exampleswas pulverized and dissolved in chloroform. After that, acetone wasadded to the solution and a precipitated resin content was removed.o-Hydroxyacetophenone in the solution after the removal of the resincontent was determined by high-performance liquid chromatography.

[Measurement of Nitrogen Atom Content]

Each of the molded bodies obtained in Examples and Comparative Exampleswas pulverized, and its nitrogen atom content was measured with amicroanalyzer “TS-100” (manufactured by Mitsubishi Chemical AnalytechCo., Ltd., mounted with a detector for nitrogen analysis: ND-100) by achemiluminescence method under the conditions of a sample amount of from1 mg to 20 mg and a combustion temperature of 1,000° C.

[Measurement of Proton NMR Spectrum]

A proton NMR spectrum was measured by using each of the molded bodiesobtained in Examples and Comparative Examples under the followingconditions, and the ratio of a total signal intensity observed in thechemical shift region of from 6.3 ppm or more to 6.7 ppm or less when atotal signal intensity observed in the chemical shift region of from 1.5ppm or more to 1.9 ppm or less was defined as 100 was determined. Achemical shift value was determined with reference to a signal (1.67ppm) of a proton of the isopropylidene group of bisphenol A in thearomatic polycarbonate resin.

Measuring apparatus: “ECA 500” (manufactured by JEOL RESONANCE Inc.)

Measurement solvent: CDCl₃

Flip angle: 45°

Repetition time: 9 seconds

Cumulative number: 256 times

Observed range: 20 ppm

Observation center: 5 ppm

[Measurement of YI Value]

A resin pellet was dried at 110° C. for 5 hours, and was then moldedinto flat plate-shaped molded bodies each measuring 50 mm by 90 mm by 5mm thick with an injection molding machine “NISSEI ES 1000”(manufactured by Nissei Plastic Industrial Co., Ltd., clamping force: 80t) at cylinder preset temperatures of 280° C. and 360° C., and a dietemperature of 80° C. for a cycle time of 50 seconds.

The YI values of the resultant molded bodies were measured with aspectrophotometer “U-4100” (manufactured by Hitachi High-TechnologiesCorporation) under the conditions of a C light source and a two-degreefield of view. It should be noted that an acceptance criterion is asfollows: the YI value of the molded body obtained by the molding at 360°C. is 1.21 or less.

[Measurement of L Value]

The L values of the flat plate-shaped molded bodies each measuring 50 mmby 90 mm by 5 mm thick produced at a cylinder preset temperature of 360°C., and a die temperature of 80° C. for a cycle time of 50 seconds weremeasured with a spectrophotometer “U-4100” (manufactured by HitachiHigh-Technologies Corporation) under the conditions of a D65 lightsource and a ten-degree field of view.

[Component Composition]

Components used in Examples and Comparative Examples are as describedbelow.

<Aromatic Polycarbonate Resin (A)>

(A1): “TARFLON FN1500” (manufactured by Idemitsu Kosan Co., Ltd.,bisphenol A polycarbonate resin, viscosity-average molecular weight:14,500)

(A2): TARFLON FN1200 (manufactured by Idemitsu Kosan Co., Ltd.,bisphenol A polycarbonate resin, viscosity-average molecular weight:11,500)

(A3): bisphenol A polycarbonate resin (PC-1) obtained in ProductionExample 1 (viscosity-average molecular weight: 14,300)

(A4): bisphenol A polycarbonate resin (PC-2) obtained in ProductionExample 2 (viscosity-average molecular weight: 14,200)

(A5): bisphenol A polycarbonate resin (PC-3) obtained in ProductionExample 3 (viscosity-average molecular weight: 14,600)

<Polyether Compound (b1) having Polyoxyalkylene Structure>

(b1-1): “POLYCERIN DC-1100” (manufactured by NOF Corporation,polyoxytetramethylene glycol-polyoxyethylene glycol)

(b1-2): “POLYCERIN DC-3000E” (manufactured by NOF Corporation,polyoxytetramethylene glycol-polyoxyethylene glycol)

(b1-3): “UNIOX GT-201S” (manufactured by NOF Corporation,polyoxyethylene-triisostearic acid)

(b1-4): “UNILUB 50DB-22” (manufactured by NOF Corporation,polyoxyethylene-polyoxypropylene-bisphenol A ether)

(b1-5): “EPIOL E-1000” (manufactured by NOF Corporation, polyethyleneglycol diglycidyl ether)

<Acid-Generating Compound (b2)>

(b2-1): phenylboronic acid anhydride (manufactured by Hokko ChemicalIndustry Co., Ltd.)

(b2-2): 4-methoxyphenylboronic acid anhydride (manufactured by HokkoChemical Industry Co., Ltd.)

(b2-3): butyl p-toluenesulfonate (manufactured by Wako Pure ChemicalIndustries, Ltd.)

(b2-4): octyl p-toluenesulfonate (manufactured by Wako Pure ChemicalIndustries, Ltd.)

<Antioxidant (C)>

(C1): “Doverphos S-9228PC” (manufactured by Dover Chemical Corporation,bis(2,4-dicumylphenyl)pentaerythritol diphosphite, production amounts ofdicumylphenol after a hydrolysis resistance test: 0.15 mass %)

(C2): “ADK STAB 2112” (manufactured by ADEKA Corporation,tris-2,4-di-tert-butylphenyl phosphite, production amounts of2,4-di-tert-butylphenol after a hydrolysis resistance test: 6 mass %)

<Other Components>

“MACROLEX VIOLET 3R” (manufactured by LANXESS AG, a bluing agent havingan absorption maximum at a wavelength of 558 nm)

“PSJ-POLYSTYRENE GPPS 679” (manufactured by PS Japan Corporation,polystyrene)

TABLE 1 Example Unit 1 2 3 4 5 6 Resin molding Aromatic (A1) TARFLONFN1500 Part(s) 100 100 100 100 material polycarbonate (A2) TARFLONFN1200 by mass 100 100 composition resin (A) (A3) PC-1 (A4) PC-2 (A5)PC-3 Polyether (b1-1) POLYCERIN DC1100 Part(s) 0.2 0.4 compound (b1-2)POLYCERIN DC3000E by mass 0.2 (b1) (b1-3) UNIOX GT-20IS 0.2 (b1-4)UNILUB 50DB-22 0.2 (b1-5) EPIOL E-1000 0.2 Acid- (b2-1) Phenylboronicacid anhydride Part(s) generating (b2-2) 4-Methoxyphenylboronic acid bymass compound anhydride (b2) (b2-3) Butyl p-toluenesulfonate (b2-4)Octyl p-toluenesulfonate Antioxidant (C1) Doverphos S-9228PC Part(s)0.05 0.05 0.05 0.05 0.05 0.05 (C) (C2) ADK STAB 2112 by mass OtherMACROLEX VIOLET 3R ppb component PSJ-POLYSTYRENE GPPS 679 Part(s) bymass Evaluation result o-Hydroxyacetophenone content (molding at 360°C./50 mm ppm by 0.30 0.30 0.20 0.30 0.30 0.20 by 80 mm by 0.3 mm thick)mass* Nitrogen atom content (molding at 360° C./50 mm by ppm* 8 8 8 8 1010 80 mm by 0.3 mm thick) Presence or absence of absorption maximum in —A A A A A A wavelength range of from 500 nm to 600 nm (molding at 360°C./50 mm by 80 mm by 0.3 mm thick) Signal intensity ratio** of protonNMR (molding at — 0.07 0.07 0.07 0.07 0.09 0.09 360° C./50 mm by 80 mmby 0.3 mm thick) YI value (molding at 280° C./50 mm by 90 mm by 5 mm —1.00 1.00 0.90 1.08 1.11 1.02 thick) YI value (molding at 360° C./50 mmby 90 mm by 5 mm — 1.01 1.05 0.95 1.11 1.13 1.08 thick) L value (moldingat 360° C./50 mm by 90 mm by 5 mm — 96.01 96.01 96.03 95.97 95.96 95.99thick) Example Unit 7 8 9 10 11 Resin molding Aromatic (A1) TARFLONFN1500 Part(s) 100 100 100 material polycarbonate (A2) TARFLON FN1200 bymass composition resin (A) (A3) PC-1 100 (A4) PC-2 100 (A5) PC-3Polyether (b1-1) POLYCERIN DC1100 Part(s) 0.3 compound (b1-2) POLYCERINDC3000E by mass (b1) (b1-3) UNIOX GT-20IS (b1-4) UNILUB 50DB-22 (b1-5)EPIOL E-1000 Acid- (b2-1) Phenylboronic acid anhydride Part(s) 0.2generating (b2-2) 4-Methoxyphenylboronic acid by mass 0.1 compoundanhydride (b2) (b2-3) Butyl p-toluenesulfonate 0.001 (b2-4) Octylp-toluenesulfonate 0.005 Antioxidant (C1) Doverphos S-9228PC Part(s)0.05 0.05 0.05 0.05 0.05 (C) (C2) ADK STAB 2112 by mass Other MACROLEXVIOLET 3R ppb component PSJ-POLYSTYRENE GPPS 679 Part(s) by massEvaluation result o-Hydroxyacetophenone content (molding at 360° C./50mm ppm by 0.10 0.10 0.80 0.40 0.10 by 80 mm by 0.3 mm thick) mass*Nitrogen atom content (molding at 360° C./50 mm by ppm* 8 8 8 7 4 80 mmby 0.3 mm thick) Presence or absence of absorption maximum in — A A A AA wavelength range of from 500 nm to 600 nm (molding at 360° C./50 mm by80 mm by 0.3 mm thick) Signal intensity ratio** of proton NMR (moldingat — 0.07 0.07 007 0.07 0.08 360° C./50 mm by 80 mm by 0.3 mm thick) YIvalue (molding at 280° C./50 mm by 90 mm by 5 mm — 1.01 1.04 1.04 1.030.90 thick) YI value (molding at 360° C./50 mm by 90 mm by 5 mm — 1.111.09 1.16 1.11 0.92 thick) L value (molding at 360° C./50 mm by 90 mm by5 mm — 95.97 95.98 95.94 95.96 96.05 thick) Comparative Example Unit 1 23 4 5 Resin molding Aromatic (A1) TARFLON FN1500 Part(s) 100 100 100material polycarbonate (A2) TARFLON FN1200 by mass composition resin (A)(A3) PC-1 100 (A4) PC-2 (A5) PC-3 100 Polyether (b1-1) POLYCERIN DC1100Part(s) 0.2 0.005 compound (b1-2) POLYCERIN DC3000E by mass (b1) (b1-3)UNIOX GT-20IS (b1-4) UNILUB 50DB-22 (b1-5) EPIOL E-1000 Acid- (b2-1)Phenylboronic acid anhydride Part(s) generating (b2-2)4-Methoxyphenylboronic acid by mass compound anhydride (b2) (b2-3) Butylp-toluenesulfonate (b2-4) Octyl p-toluenesulfonate Antioxidant (C1)Doverphos S-9228PC Part(s) 0.05 0.05 0.05 (C) (C2) ADK STAB 2112 by mass0.05 0.05 Other MACROLEX VIOLET 3R ppb 100 component PSJ-POLYSTYRENEGPPS 679 Part(s) 0.05 by mass Evaluation result o-Hydroxyacetophenonecontent (molding at 360° C./50 mm ppm by 1.50 2.00 0.70 0.10 1.30 by 80mm by 0.3 mm thick) mass* Nitrogen atom content (molding at 360° C./50mm by ppm* 8 8 20 7 10 80 mm by 0.3 mm thick) Presence or absence ofabsorption maximum in — A A A P A wavelength range of from 500 nm to 600nm (molding at 360° C./50 mm by 80 mm by 0.3 mm thick) Signal intensityratio** of proton NMR (molding at — 0.07 0.07 0.10 0.23 <0.05 360° C./50mm by 80 mm by 0.3 mm thick) YI value (molding at 280° C./50 mm by 90 mmby 5 mm — 1.22 1.23 1.28 1.01 1.15 thick) YI value (molding at 360°C./50 mm by 90 mm by 5 mm — 1.27 1.35 1.43 1.30 1.25 thick) L value(molding at 360° C./50 mm by 90 mm by 5 mm — 95.85 95.83 95.80 95.7095.93 thick) *Content in a molded body **The ratio of a total signalintensity observed in the chemical shift region of from 6.3 ppm or moreto 6.7 ppm or less when a total signal intensity observed in thechemical shift region of from 1.5 ppm or more to 1.9 ppm or less isdefined as 100 A: Absent; P: Present

As can be seen from Table 1, the aromatic polycarbonate resin moldedbody of the present invention is reduced in yellowing and is excellentin light transmission property. In contrast, the yellowing of thepolycarbonate resin molded body of Comparative Examples is remarkable.

INDUSTRIAL APPLICABILITY

According to the present invention, there can be provided an aromaticpolycarbonate resin molded body that has a thin-walled portion having athickness of 0.5 mm or less, is reduced in yellowing, and is excellentin light transmission property.

The invention claimed is:
 1. An aromatic polycarbonate resin moldedbody, which is obtained by molding a resin molding material comprisingan aromatic polycarbonate resin (A), wherein: the molded body has athin-walled portion having a thickness of 0.5 mm or less; the moldedbody has an o-hydroxyacetophenone content of 1 ppm by mass or less and anitrogen atom content of 15 ppm or less; and the molded body is free ofan absorption maximum in a wavelength range of from 500 nm to 600 nm. 2.The aromatic polycarbonate resin molded body according to claim 1,wherein a length in a longitudinal direction of the molded body is 60 mmor more, and a thickness of a region accounting for at least 80% of themolded body is 0.7 mm or less.
 3. The aromatic polycarbonate resinmolded body according to claim 1, wherein when a total signal intensityobserved in a chemical shift region of from 1.5 ppm or more to 1.9 ppmor less at a time of measurement of a proton NMR spectrum is defined as100, the molded body has a ratio of a total signal intensity observed ina chemical shift region of from 6.3 ppm or more to 6.7 ppm or less of0.15 or less.
 4. The aromatic polycarbonate resin molded body accordingto claim 1, wherein the resin molding material further comprises apolyether compound (b1) having a polyoxyalkylene structure.
 5. Thearomatic polycarbonate resin molded body according to claim 1, whereinthe resin molding material further comprises an acid-generating compound(b2).
 6. The aromatic polycarbonate resin molded body according to claim5, wherein the acid-generating compound (b2) comprises at least oneselected from a boronic acid anhydride and a sulfonate.
 7. The aromaticpolycarbonate resin molded body according to claim 4, wherein a contentof the polyether compound (b1) is from 0.01 part by mass to 5 parts bymass with respect to 100 parts by mass of the aromatic polycarbonateresin (A).
 8. The aromatic polycarbonate resin molded body according toclaim 5, wherein a content of the acid-generating compound (b2) is from0.0001 part by mass to 0.5 part by mass with respect to 100 parts bymass of the aromatic polycarbonate resin (A).
 9. The aromaticpolycarbonate resin molded body according to claim 1, wherein thearomatic polycarbonate resin (A) has a viscosity-average molecularweight (Mv) of from 10,000 to 50,000.
 10. A light-guiding plate,comprising the aromatic polycarbonate resin molded body of claim 1.